Gas fired apparatus, such as residential gas fired water heaters, often include a main gas burner to provide heat for the apparatus, and a pilot burner that provides a standing pilot flame to ignite the main gas burner (e.g., for the first time or if the main burner flame goes out). In the case of water heaters, a main gas burner is used to heat water within a water tank of the water heater. A thermostat is typically provided to control the temperature of the water inside the tank and typically may be set within a particular range (e.g., warm, hot or very hot). A pilot burner provides a standing pilot flame to ignite the main gas burner.
To ignite the pilot flame in typical gas fired apparatus, a user holds a pilot valve open (e.g., with a depressible knob) to permit gas to flow to the pilot burner, and ignites the gas at the pilot burner with an ignition source, such as an electronic igniter or a match. A main burner valve which controls the flow of gas to the main burner is typically closed when the pilot light is being lit. However, abnormal operating conditions may cause the main burner valve to be open when the pilot light is being lit, allowing combustible gases to flow to the main burner and creating hazardous ignition conditions. Additionally, some gas flow controllers allow the pilot valve to be opened under abnormal operating conditions, such as an elevated pressure condition on the inlet or upstream side of the pilot valve. This may result in excessive gas flow to the pilot burner, and excessive strain on components of the gas flow controller that interconnect the pilot valve with a user input device used to actuate the pilot valve.
At least some known gas flow controllers lack redundancy during the pilot lighting sequence, or are subject to potential software failure modes. Additionally, at least some known gas flow controllers utilize electronically controlled valves and/or relatively large valves as safety features, which add to the size, complexity, and cost of the gas flow controllers. Moreover, some gas flow controllers control actuation of the pilot valve with an electro-magnet that draws power from a relatively limited power supply, such as a millivolt power source, used to control operation of the gas flow controller.
This Background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.